The Simons Foundation has given $38.4 million to establish a new astronomy facility in Chile's Atacama Desert, adding new telescopes and detectors alongside existing instruments in order to boost ongoing studies of the evolution of the universe, from its earliest moments to today. The Heising-Simons Foundation is providing an additional $1.7 million for the project.

The Simons Array will be located in Chile's High Atacama Desert, at an elevation of about 17,000 ft. The site currently hosts the Atacama Cosmology Telescope (bowl-shaped structure at upper right) and the Simons Array (the three telescopes at bottom left, center and right). The Simons Observatory will merge these two experiments, add several new telescopes and set the stage for a next-generation experiment. Courtesy of the University of Pennsylvania.
The Simons Observatory is a collaboration among the U.S. Department of Energy's Lawrence Berkeley National Laboratory, UC Berkeley, Princeton University, the University of California at San Diego and University of Pennsylvania, all of which are also providing financial support.

The observatory will probe cosmic microwave background (CMB) radiation, subtle properties of the universe's first light, paying particular attention to the polarization in the CMB light to better understand what took place a fraction of a second after the Big Bang.

A view of the Atacama Cosmology Telescope (ACT) in Chile's High Atacama Desert. ACT, in operation since 2006, has taken measurements of the cosmic microwave background (CMB) and of massive galaxy clusters. The Simons Observatory will consolidate experiments and add telescopes and other new equipment at this site. Courtesy of Mark Devlin/University of Pennsylvania.
A key goal of the project is to detect gravitational waves generated by cosmic inflation, an extraordinarily rapid expansion of space that, according to the most popular cosmological theory, took place in an instant after the Big Bang. These primordial gravitational waves induced a very small but characteristic polarization pattern, called B-mode polarization, in the microwave background radiation that can be detected by telescopes and cameras like those planned for the Simons Observatory.

The Milky Way's galactic plane rises above the Atacama Cosmology Telescope. The Simons Observatory is planned at the same site in Chile's High Atacama Desert and will merge existing experiments and add new telescopes and detectors. Courtesy of Jon Ward/University of Pennsylvania.
By measuring how radiation from the early universe changed as it traveled through space to Earth, the observatory also aims to better understand nature of dark energy and dark matter, the properties of neutrinos, and how large-scale structure formed as the universe expanded and evolved.

Two existing instruments at the site — the Atacama Cosmology Telescope and the Simons Array — are currently measuring polarization. The foundation funds will merge these two experiments, expand the search, and develop new technology for a fourth-stage, next-generation project — CMB-Stage 4 — that researchers believe could mine all the cosmological information in the cosmic microwave background fluctuations possible from a ground-based observatory.

The Atacama Cosmology Telescope, pictured here, will merge with another set of instruments, the Simons Array, and new telescopes and equipment will be added at the site with the launch of the Simons Observatory project. Courtesy of Princeton University.
Experiments at the Atacama site have paved the way for CMB-Stage 4. A 2012 UC Berkeley-led experiment with participation by Berkeley Lab researchers, called POLARBEAR, used a 3.5-m telescope to measure the gravitational-lensing-generated B-mode polarization of the cosmic microwave background radiation. Team scientists confirmed in 2014 that the signal was strong enough to allow them eventually to measure the neutrino mass and the evolution of dark energy.

The recent addition of two more telescopes upgrades POLARBEAR to the Simons Array, which will speed up the mapping of the CMB and improve sky and frequency coverage. The $40 million in new funding will make possible the successor to the Simons Array and the nearby Atacama Cosmology Telescope.

The scientific observation of celestial radiation that has reached the vicinity of Earth, and the interpretation of these observations to determine the characteristics of the extraterrestrial bodies and phenomena that have emitted the radiation.